S-Transform based technique to detect high resistance symmetrical fault during power swing

Distance relay is designed to operate when fault occurs in the system, but still should block the operation when power swing occurs in the system. However, this blocking scheme prove to vulnerable to distance relay operation as it could block the trip signals when a genuine fault occurs in the system during power swing. Hence, it is desired to develop the proper fault detection technique during power swing to avoid such circumstances. This paper presents S-Transform based detection technique to detect symmetrical fault with high resistance up to 200 Ω during power swing. The proposed scheme is based on S-Transform analysis on the current and voltage waveforms. The effectiveness of the proposed scheme was verified with the IEEE 14 bus test system and simulations results show that the proposed technique can detect high resistance symmetrical fault occurring during power swing from 5 Ω up to 200 Ω.